THE NATIONAL NURSERYMAN 
138 
IMPORTATION OF EUROPEAN PINE PROHIBITED. 
Danger From Fine Shoot Moth Results in Absolute 
Quarantine After July 1. 
No European pine trees will be permitted to be im¬ 
ported into the United States after July 1, a quarantine 
order to this effect having been signed by the Secretary 
of Agriculture. This action has been taken to save Amer¬ 
ican pine trees from the pine shoot moth which lias long 
done much damage in European forests. This pest has 
already become established in nurseries and parks in 
•some States but it is believed that by pruning and de¬ 
stroying the affected shoots the disease can be stamped 
out ll no more infected nursery stock is imported into the 
country. 
The European pine shoot moth eats out the new buds 
and kills or deforms the young twigs of pine trees in such 
a way that the timber value is seriously and permanently 
lowered. The moth feeds mostly on young trees be¬ 
tween 6 and 15 years of age, destroying a large number 
of buds and young shoots and injuring adjoining ones. 
These injured shoots bend downward and outward, after¬ 
wards growing upward again. When the pest is abun¬ 
dant the trees are rendered unsightly and crippled and of 
no commercial value. 
The moth lays its eggs early in August singly on the 
new buds of the pine. The young larva soon hatches 
and eats its way into the bud where it spends the winter. 
As soon as the sap begins to rise in the trees it leaves its 
winter quarters and bores into the adjoining bud, de¬ 
stroying this and as many others as it needs for food. 
When the remaining buds begin to grow into young 
shoots, the larva attacks these as well, consuming the en¬ 
tire inside of the youngest and injuring the more devel¬ 
oped ones so that they grow downward and outward in¬ 
stead of upward. It is impossible to reach the larva 
with any insecticide after it has once found its winter 
quarters, and the only effective way of combating the 
pest is to destroy the infected buds and twigs. Pruning 
of this kind in the fall and winter months will minimize 
the damage in the spring, but it is more difficult to deter¬ 
mine the existence of the pest at this time than when the 
injury is further developed. A little practice, however, 
will enable the nurseryman to recognize the trace of 
pitch at the base of the bud covering the entrance hole of 
the larva. 
‘MANY CULTIVATED AMERICAN PLUMS ORIGIN¬ 
ATED FROM WILD NATIVE VARIETIES. 
The wild North American plum has given rise to more 
cultivated varieties than any other of the native fruits 
except the grape. These varieties have mainly origin¬ 
ated in the Mississippi Valley, Iowa alone having fur¬ 
nished 175, Minnesota 74, and South Dakota 44. In 
Texas 97 varieties have originated. In these western 
and southern regions where several of the species appear 
to have reached their greatest perfection in the wild con¬ 
dition the greatest development in the future, under cul¬ 
tivation, may probably also be expected to take place, ac¬ 
cording to a new bulletin of the U. S. Department of Agri¬ 
culture (No. 172) entitled “The Varieties of Plums De¬ 
rived From Native American Species.” 
The new publication is a professional paper which 
should be of especial interest to the growers of fruit, par¬ 
ticularly those engaged in plum breeding. It gives a 
list of native varieties and hybrids showing the origin of 
each variety and the species to which it belongs, which 
should be of considerable value to the nurseryman and 
orchardist. It also gives credit to the various State ex¬ 
periment stations and private individuals who have fur¬ 
nished material used in investigating the origin and re¬ 
lationships of the varieties under consideration. 
With few fruits has there been an equal opportunity to 
report step by step the advance which has been made 
since the original of the first named variety ^vas planted 
and cultivated in a garden. The new bulletin, therefore, 
places on record a distinct achievement of American hor¬ 
ticulturists who have developed a fruit, the value of 
which was long overlooked. 
Interested horticulturists may receive the bulletin if 
they will apply to the Editor and Chief, Division of Pub¬ 
lications, U. S. Department of Agriculture, Washington, 
D. G.- 
RINGING FRUIT TREES 
In a bulletin issued by the New York Agricultural Ex¬ 
periment Station G. II. Howe summarizes the results of 
the ringing of fruit trees as follows: 
1. The object of ringing fruit trees is to induce unpro¬ 
ductive trees to set fruit. 
2. Briefly stated, the theory of the operation is: That 
the removal of a band of bark through the cortex and 
bast of a plant, at the period of most vigorous growth, 
does not hinder the upward passage from the roots to the 
leaves, through the outer layer of woody cells, of un- 
assimilated sap; but does prevent the distribution, 
through vessels in the cortex and inner bark below the 
wound, of assimilated food. The eff ect of this action is 
to cause an extra amount of reserve material to be stored 
in the upper parts of the plant for the production of fruit 
buds. 
3. Ringing seems to favor certain organs for a time 
but devitalizes others. 
4. The removal of narrow strips of bark is less in¬ 
jurious to plant growth than taking out wide rings. 
5. Under certain conditions, ringing may induce and 
possibly increase fruitfulness of apples, but it rarely has 
these favorable effects on other fruits. 
6. Only young and very vigorous apple trees, possibly 
now and then pear and cherry trees, can survive ringing, 
and even with these fruits the compensating gains seldom 
offset the injury to the trees. 
7. The practice of ringing stone fruits should never 
be followed. The experiments indicate almost 100 per 
cent, loss in the life of the trees. 
8. Regular and successive increases in productive¬ 
ness did not result from the ringing of several varieties of 
our tree fruits. 
9. Ringing had no apparent influence upon the size, 
color or maturity of apples. 
10. The general effect of ringing on the roots of the 
trees was to decrease their size and number and to lessen 
their vigor. 
